It is written in Java script and it is supposed to be a high productivity tool. It is even supposed to be way faster than the way Mindmanager functions. And this while in my opinion Mindmanager is one of the fastest software packages as long as we are talking about mind mapping software. 

What makes FreeMind so special?

• You can use HTML and internal links with this software. Whatever you do, the links will be executable within a mind map produced.
• Folding and unfolding the nodes/branches is supposed to be the essential property of this free mind mapping software package.
• Every mind map produced with this software can be exported to HTML. You can also easily import from text, RTF, Wordpad, Word and Outlook messages.
• Nodes/branches can be decorated with color, built-in icons and diverent styles of fonts.

Weaknesses of this free mind mapping software package:

• We all know that a picture can say a thousand words. So why is this package so weak with the support of pictures. Appearantly you need to carry around your image files with you if you want to carry around with your mind maps.
• This software is not good to work with groups. It is build to be a one user application. So if you want to work as a team on one project, you have a problem with this software package.
• The HTML links do not work on all computers. This means the reliability of the software is not good.
• But the biggest problem is and remains the fact that this packages is very weak on the end of pictures and fancy graphics.

What are your alternatives?

 Thinkgraph   , VYM - View Your Mind (http://www.insilmaril.de/vym/) or Kdissert .